Foam debris caused the damage to Columbia's heat tiles which led to the shuttle disaster. NASA made changes to the external fuel tank but continued to lose foam on the first return-to-space flight. NASA Space Shuttle Program Manager Wayne Hale says a power ramp lost a pound of foam during that launch. He says they've decided to eliminate that ramp.
"That change constitutents the largest aerodynamic change that we have made to the space shuttle launch system since it first flew. We are approaching that with a great deal of care, doing the work necessary to prove that the aerodynamics will still be good."
It's also known that ice frost ramps can lose up to three-and-a-half ounces of foam. While NASA will continue to address that problem, Hale says he doesn't want to make any other major structural changes to the orbitor without a flight.
"It is more appropriate to make one change at a time, to take care of the biggest problem that we have and then work our way to the next situation we'd like to improve and I expect that will be the story of the external tank for the remainder of the life of the space shuttle program."
NASA plans to retire the space shuttle program in 2010. Capella Tucker, Houston Public Radio News.